Biodegradable Polyester Composition for Transparency and Impact Strength
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Solution Overview
Problem
Existing biodegradable polyester polymers, such as PLA and PBAT, face challenges in achieving a balance between transparency and impact strength, with compatibility issues leading to deteriorated mechanical and thermal properties when blended.
Innovation Solution
A biodegradable polyester polymer is developed using a polymerizable composition comprising aromatic dicarboxylic acid or dialkylcarboxylate, aliphatic dicarboxylic acid, aliphatic glycol, and a polypropylene sebacate oligomer with a weight average molecular weight of 2,000 to 8,000 g/mol, enhancing transparency and impact strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If PLA and PBAT are blended to complement physical properties, then impact strength is improved, but transparency deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the molecular weight of the oligomer component within a specific range (weight average molecular weight of 2,000 to 8,000 g/mol) and optimizing the compositional ratios of dicarboxylic compound (30-70 wt%), glycol compound (20-60 wt%), and oligomer (5-20 wt%). This precise parameter control enables the polymer to achieve both improved impact strength and maintained transparency, resolving the contradiction between these two properties.
2Strength
If PLA and PBAT are blended, then mechanical properties are improved, but compatibility is poor leading to deteriorated properties
Solution Approach 1:
The patent uses an oligomer as an intermediary component that mediates between the dicarboxylic compound and glycol compound. This oligomer acts as a compatibility enhancer, allowing PLA and PBAT to blend effectively while maintaining good compatibility. The oligomer's specific molecular weight range (2,000-8,000 g/mol) enables it to function as an effective mediator, preventing phase separation and maintaining homogeneous composition, thus resolving the compatibility issue while improving mechanical strength.
3Strength
If additives are added to improve compatibility, then physical properties are improved, but low molecular weight compounds are included making packaging use difficult
Solution Approach 1:
The patent resolves this contradiction by changing the parameter of molecular weight from low (additives) to controlled oligomer range (2,000-8,000 g/mol). The oligomer, while having lower molecular weight than full polymers, is sufficiently high to avoid the harmful effects of low molecular weight compounds. This parameter optimization allows the material to achieve improved compatibility and physical properties while remaining suitable for packaging applications where low molecular weight compounds would be problematic.
Data Source
AI summary
The present invention relates to a biodegradable polyester polymer with excellent transparency and impact strength and a biodegradable polymer composition comprising same. Particularly, the biodegradable polyester polymer is prepared from: a dicarboxylic compound including aromatic dicarboxylic acid or aromatic dialkylcarboxylate, and aliphatic dicarboxylic acid; an aliphatic glycol compound; and a polymerizable composition including a polypropylene sebacate oligomer, and thus can realize improved transparency and impact strength.